Chemical-mechanical etch (CME) method for patterned etching of a substrate surface

Abstract

Chemical-mechanical processing of a patterned substrate selectively etches patterned portions of the substrate surface, producing deep narrow features with a rapid etch rate. This chemical-mechanical processing is termed chemical-mechanical etching and produces a result that is substantially the opposite of the planarization that is achieved by conventional chemical-mechanical polishing (CMP). A chemical-mechanical polishing (CMP) technique which is widely used for planarization of surfaces is converted for usage as an etching technique, a chemical-mechanical etching (CME) technique, by forming a patterned mask on the substrate surface prior to mechanical polishing. The usage of chemical-mechanical polishing techniques in this manner yields an etching method with properties including a rapid etch rate, a highly controllable etch rate, a highly controllable etch depth, and a greatly selective etch directionality. A coating that inhibits the removal of the substrate material protects selectively patterned areas of a substrate, thereby creating a recess in substrate areas that are not protected by the coating.

What is claimed is:  
     
       1. A method of etching a substrate comprising: 
       forming a patterned protective layer composed of a hard material on a surface of a substrate; and  
       chemical-mechanical etching (CME) the substrate using a chemical-mechanical polishing technique to form an etched substrate structure having elevated structures in regions of the substrate that are protected by the patterned protective layer and having trenches in regions of the substrate that are not protected by the patterned protective layer.  
     
     
       2. A method according to  claim 1  wherein: 
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       3. A method according to  claim 2  wherein: 
       the forming step includes the step of forming the diamond-like carbon (DLC) patterned protective layer with a Knoop hardness in a range from approximately 700 to approximately 2000.  
     
     
       4. A method according to  claim 1  further comprising: 
       chemical-mechanical etching (CME) the substrate so that the elevated structures have substantially vertical side walls.  
     
     
       5. A method according to  claim 1  further comprising: 
       chemical-mechanical etching (CME) the substrate so that the trench structures have a substantially uniform depth.  
     
     
       6. A method according to  claim 1  further comprising: 
       providing a glass substrate; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       7. A method according to  claim 1  further comprising: 
       providing an alumina substrate; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       8. A method according to  claim 1  further comprising: 
       providing a substrate selected from among silicon, silicon dioxide, silicon nitride, gallium arsenide, polyimide, photoresist, aluminum, tungsten, molybdenum, and titanium; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       9. A method according to  claim 1  wherein the forming step includes: 
       depositing a silicon adhesion layer on a surface of the substrate; and  
       depositing a patterned protective layer composed of diamond-like carbon (DLC).  
     
     
       10. A method according to  claim 1  wherein: 
       the CME step includes the step of contouring the thin film substrate using a orbital, planetary motion.  
     
     
       11. A method according to  claim 1  wherein: 
       the CME step includes the step of contouring the thin film substrate using a rectilinear motion.  
     
     
       12. A method according to  claim 1  further comprising: 
       patterning the patterned protective layer using a reactive ion etch process.  
     
     
       13. A method of etching a substrate comprising: 
       providing a substrate wafer having a surface;  
       forming a hard patterned protective layer on a surface of a substrate to form protected regions and unprotected regions of the substrate surface; and  
       chemical-mechanical polishing (CMP) the substrate, the chemical-mechanical polishing step etching the substrate in unprotected regions to form trenches adjacent to the protected regions of the substrate surface.  
     
     
       14. A method according to  claim 13 , further comprising: 
       chemical-mechanical polishing (CMP) the substrate so that the elevated structures have substantially vertical side walls.  
     
     
       15. A method according to  claim 13  further comprising: 
       chemical-mechanical polishing (CMP) the substrate so that the trench structures have a substantially uniform depth.  
     
     
       16. A method according to  claim 13  wherein: 
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       17. A method according to  claim 16  wherein: 
       the forming step includes the step of forming the diamond-like carbon (DLC) patterned protective layer with a Knoop hardness in a range from approximately 700 to approximately 2000.  
     
     
       18. A method according to  claim 13  further comprising: 
       providing a glass substrate; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       19. A method according to  claim 13  further comprising: 
       providing an alumina substrate; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       20. A method according to  claim 13  further comprising: 
       providing a substrate selected from among silicon, silicon dioxide, silicon nitride, gallium arsenide, polyimide, photoresist, aluminum, tungsten, molybdenum, and titanium; wherein  
       the forming step includes the step of forming a patterned protective layer composed of a hard material is composed of diamond-like carbon (DLC).  
     
     
       21. A method according to  claim 13  wherein the forming step includes: 
       depositing a silicon adhesion layer on a surface of the substrate; and  
       depositing a patterned protective layer composed of diamond-like carbon (DLC).  
     
     
       22. A method according to  claim 13  further comprising: 
       patterning the patterned protective layer using a reactive ion etch process.